Kidney Ischemia-reperfusion Research Articles

Female sex hormones inversely regulate acute kidney disease susceptibility throughout life.

While epidemiological and experimental studies have demonstrated kidney-protective effects of estrogen and female sex in adulthood, some epidemiological data showed deterioration of kidney function during puberty when estrogen production increases. However, molecular mechanisms explaining these conflicting phenomena remain unknown. Here, we showed that the pubertal sex hormone surge in female mice increases susceptibility to kidney ischemia reperfusion injury partly via downregulation of insulin-like growth factor 1 receptor (IGF-1R) expression in proximal tubules. Adult mice ovariectomized pre-pubertally (at postnatal day 21) showed strong tolerance to kidney ischemia, which was partly reversed by the administration of 17β-estradiol, while adult mice ovariectomized post-pubertally (at 8 weeks of age) were vulnerable to kidney ischemia. Kidney tubular IGF-1R protein expression decreased during postnatal growth but was highly expressed in adult mice ovariectomized pre-pubertally and in infant mice, which might be partly explained by different expression of an E3 ligase (MDM2) of IGF-1R. Mice deficient of Igf-1r in proximal tubules (iIGF-1RKO mice) during postnatal kidney growth showed increased susceptibility to ischemic injury. RNA-seq and western blotting analysis using proximal tubular cells from pre-pubertally ovariectomized iIGF-1RKO and control mice revealed altered expression of cell cycle-associated molecules such as cyclin D1. These results suggest that Igf-1r deletion during postnatal growth renders proximal tubular cells susceptible to ischemia possibly via altered cell cycle regulation. Thus, our findings provide evidence that exposure to pubertal sex hormones leads to increased susceptibility to kidney ischemia, which is partly mediated by modulation of IGF-1R signaling.

Magnetic vagus nerve stimulation ameliorates contrast-induced acute kidney injury by circulating plasma exosomal miR-365-3p

BackgroundContrast-induced acute kidney injury (CI-AKI) is manifested by a rapid decline in renal function occurring within 48–72 h in patients exposed to iodinated contrast media (CM). Although intravenous hydration is currently the effective method confirmed to prevent CI-AKI, it has several drawbacks. Some investigations have demonstrated the nephroprotective effects of vagus nerve stimulation (VNS) against kidney ischemia-reperfusion injury, but no direct research has investigated the use of VNS for treating CI-AKI. Additionally, most current VNS treatment applies invasive electrical stimulator implantation, which is largely limited by the complications. Our recent publications introduce the magnetic vagus nerve stimulation (mVNS) system pioneered and successfully used for the treatment of myocardial infarction. However, it remains uncertain whether mVNS can mitigate CI-AKI and its specific underlying mechanisms. Therefore, we herein evaluate the potential therapeutic effects of mVNS on CM-induced nephropathy in rats and explore the underlying mechanisms.ResultsmVNS treatment was found to significantly improve the damaged renal function, including the reduction of elevated serum creatinine (Scr), blood urea nitrogen (BUN), and urinary N-acetyl-β-D-glucosaminidase (NAG) with increased urine output. Pathologically, mVNS treatment alleviated the renal tissue structure injury, and suppressed kidney injury molecule-1 (KIM-1) expression and apoptosis in renal tubular epithelial cells. Mechanistically, increased circulating plasma exosomal miR-365-3p after mVNS treatment enhanced the autophagy and reduced CM-induced apoptosis in renal tubular epithelial cells by targeting Ras homolog enriched in brain (Rheb).ConclusionsIn summary, we demonstrated that mVNS can improve CI-AKI through enhanced autophagy and apoptosis inhibition, which depended on plasma exosomal miR-365-3p. Our findings highlight the therapeutic potential of mVNS for CI-AKI in clinical practice. However, further research is needed to determine the optimal stimulation parameters to achieve the best therapeutic effects.Graphical abstract

HSPA12A stimulates "Smurf1-Hif1α-aerobic glycolysis" axis to promote proliferation of renal tubular epithelial cells after hypoxia/reoxygenation injury.

Proliferation of renal tubular epithelial cells (TECs) is critical for the recovery after kidney ischemia/reperfusion (KI/R). However, there is still a lack of ideal therapies for promoting TEC proliferation. Heat shock protein A12A (HSPA12A) shows abundant expression in kidney in our previous studies. To investigate the role of HSPA12A in TEC proliferation after KI/R, an in vitro KI/R model was simulated by hypoxia (12h) and reoxygenation (12h) in human kidney tubular epithelial HK-2 cells. We found that, when hypoxia/reoxygenation (H/R) triggered HK-2 cell injury, HSPA12A expression was downregulated, and extracellular lactate, the readout of glycolysis, was also decreased. Loss and gain of functional studies showed that HSPA12A did not change cell viability after hypoxia but increased cell proliferation as well as glycolytic flux of HK-2 cells after H/R. When blocking glycolysis by 2-deoxy-D-glucose or oxamate, the HSPA12A promoted HK-2 cell proliferation was also abolished. Further analysis revealed that HSPA12A overexpression increased hypoxia-inducible factor 1α (Hif1α) protein expression and nuclear localization in HK-2 cells in response to H/R, whereas HSPA12A knockdown showed the opposite effects. Notably, pharmacologicalinhibition of Hif1α with YC-1 reversed the HSPA12A-induced increases of both glycolytic flux and proliferation of H/R HK-2 cells. Moreover, the HSPA12A increased Hif1α protein expression was not via upregulating its transcription but through increasing its protein stability in a Smurf1-dependent manner. The findings indicate that HSPA12A might serve as a promising target for TEC proliferation to help recovery after KI/R.

Bilirubin Nanoparticles Protect against Kidney Ischemia-Reperfusion Injury through Antioxidant Activity

Bilirubin Nanoparticles Protect against Kidney Ischemia-Reperfusion Injury through Antioxidant Activity

Remote Ischemia Precondition Protects against Kidney Ischemia-Reperfusion Injury (IRI) through Apoptosis-Associated Vesicles Carrying MIF Protein

Remote Ischemia Precondition Protects against Kidney Ischemia-Reperfusion Injury (IRI) through Apoptosis-Associated Vesicles Carrying MIF Protein

Dietary Fiber-Derived Microbial Metabolites Prevent Acute and Chronic Kidney Ischemia-Reperfusion Injury (IRI) through G Protein-Coupled Receptor GPR43

Dietary Fiber-Derived Microbial Metabolites Prevent Acute and Chronic Kidney Ischemia-Reperfusion Injury (IRI) through G Protein-Coupled Receptor GPR43

SALL1 Is Essential for Histone H3K27 Methyltransferase EZH2 to Regulate Apoptotic Responses in Kidney Ischemia-Reperfusion Injury

SALL1 Is Essential for Histone H3K27 Methyltransferase EZH2 to Regulate Apoptotic Responses in Kidney Ischemia-Reperfusion Injury

Complement C5aR-Mediated Tubular Mitochondrial Dysregulation in Kidney Ischemia-Reperfusion Injury-Induced AKI to CKD

Complement C5aR-Mediated Tubular Mitochondrial Dysregulation in Kidney Ischemia-Reperfusion Injury-Induced AKI to CKD

Time-Restricted Feeding Protects against Kidney Ischemia-Reperfusion Injury in Mice

Time-Restricted Feeding Protects against Kidney Ischemia-Reperfusion Injury in Mice

Antifibrotic Effects of Caffeic Acid in a Kidney Ischemia-Reperfusion Injured Mouse Model

Antifibrotic Effects of Caffeic Acid in a Kidney Ischemia-Reperfusion Injured Mouse Model

DNA-Binding Protein-A Promotes Kidney Ischemia-Reperfusion Injury and Participates in Mitochondrial Function

DNA-Binding Protein-A Promotes Kidney Ischemia-Reperfusion Injury and Participates in Mitochondrial Function

Metabolic Alterations in Organs and Biofluids following Unilateral Ischemia-Reperfusion Kidney Injury in Pigs

Metabolic Alterations in Organs and Biofluids following Unilateral Ischemia-Reperfusion Kidney Injury in Pigs

HSPA12A promotes c-Myc lactylation-mediated proliferation of tubular epithelial cells to facilitate renal functional recovery from kidney ischemia/reperfusion injury

Proliferation of renal tubular epithelial cells (TEC) is essential for restoring tubular integrity and thereby to support renal functional recovery from kidney ischemia/reperfusion (KI/R) injury. Activation of transcriptional factor c-Myc promotes TEC proliferation following KI/R; however, the mechanism regarding c-Myc activation in TEC is incompletely known. Heat shock protein A12A (HSPA12A) is an atypic member of HSP70 family. In this study, we found that KI/R decreased HSPA12A expression in mouse kidneys and TEC, while ablation of HSPA12A in mice impaired TEC proliferation and renal functional recovery following KI/R. Gain-of-functional studies demonstrated that HSPA12A promoted TEC proliferation upon hypoxia/reoxygenation (H/R) through directly interacting with c-Myc and enhancing its nuclear localization to upregulate expression of its target genes related to TEC proliferation. Notably, c-Myc was lactylated in TEC after H/R, and this lactylation was enhanced by HSPA12A overexpression. Importantly, inhibition of c-Myc lactylation attenuated the HSPA12A-induced increases of c-Myc nuclear localization, proliferation-related gene expression, and TEC proliferation. Further experiments revealed that HSPA12A promoted c-Myc lactylation via increasing the glycolysis-derived lactate generation in a Hif1α-dependent manner. The results unraveled a role of HSPA12A in promoting TEC proliferation and facilitating renal recovery following KI/R, and this role of HSPA12A was achieved through increasing lactylation-mediated c-Myc activation. Therefore, targeting HSPA12A in TEC might be a viable strategy to promote renal functional recovery from KI/R injury in patients.Graphical abstractHSPA12A facilitated renal functional recovery from kidney ischemia/reperfusion (KI/R) injury. This protective effect of HSPA12A was mediated through directly interacting with c-Myc as well as upregulating the Hif1α-mediated lactate generation, thereby increasing c-Myc lactylation and nuclear localization to drive expression of genes related to cell proliferation, and ultimately promoting TEC proliferation.

Prevention of Transition from Acute Kidney Injury to Chronic Kidney Disease Using Clinical-Grade Perinatal Stem Cells in Non-Clinical Study.

Acute kidney injury (AKI) is widely recognized as a precursor to the onset or rapid progression of chronic kidney disease (CKD). However, there is currently no effective treatment available for AKI, underscoring the urgent need for the development of new strategies to improve kidney function. Human placental mesenchymal stromal cells (hpMSCs) were isolated from donor placentas, cultured, and characterized with regard to yield, viability, flow cytometry, and potency. To mimic AKI and its progression to CKD in a rat model, a dedicated sensitive non-clinical bilateral kidney ischemia-reperfusion injury (IRI) model was utilized. The experimental group received 3 × 105 hpMSCs into each kidney, while the control group received IRI and saline and the untreated group received IRI only. Urine, serum, and kidney tissue samples were collected over a period of 28 days. The hpMSCs exhibited consistent yields, viability, and expression of mesenchymal lineage markers, and were also shown to suppress T cell proliferation in a dose-dependent manner. To ensure optimal donor selection, manufacturing optimization, and rigorous quality control, the rigorous Good Manufacturing Practice (GMP) conditions were utilized. The results indicated that hpMSCs increased rat survival rates and improved kidney function by decreasing serum creatinine, urea, potassium, and fractionated potassium levels. Furthermore, the study demonstrated that hpMSCs can prevent the initial stages of kidney structural fibrosis and improve kidney function in the early stages by mitigating late interstitial fibrosis and tubular atrophy. Additionally, a robust manufacturing process with consistent technical parameters was established.

228.5: Multi-omics identify PDK4 as a novel therapeutic target for kidney ischemia reperfusion.

228.5: Multi-omics identify PDK4 as a novel therapeutic target for kidney ischemia reperfusion.

Discovery of Novel Ortho-Aminophenol Derivatives Targeting Lipid Peroxidation with Potent Antiferroptotic Activities.

The concept of ferroptosis inhibition has gained growing recognition as a promising therapeutic strategy for addressing a wide range of diseases. Here, we present the discovery of four series of ortho-aminophenol derivatives as potential ferroptosis inhibitors beginning with the endogenous substance 3-hydroxyanthranilic acid (3-HA) by employing quantum chemistry techniques, in vitro and in vivo assays. Our findings reveal that these ortho-aminophenol derivatives exhibit unique intra-H bond interactions, compelling ortho-amines to achieve enhanced alignment with the aromatic π-system, thereby expanding their activity. Notably, compounds from all four series display remarkable activity against RSL3-induced ferroptosis, showcasing an activity 100 times more than that of 3-HA. Furthermore, these compounds also demonstrate robust in vivo efficacy in protecting mice from kidney ischemia-reperfusion injury and acetaminophen-induced hepatotoxicity. In summary, we provide four distinct series of active scaffolds that significantly expand the chemical space of ferroptosis inhibitors, serving as valuable insights for future structural modifications.

ROS-responsive MSC-derived Exosome Mimetics Carrying MHY1485 Alleviate Renal Ischemia Reperfusion Injury through Multiple Mechanisms.

Renal ischemia reperfusion (IR) injury is a prevalent inflammatory nephropathy in surgeries such as renal transplantation or partial nephrectomy, damaging renal function through inducing inflammation and cell death in renal tubules. Mesenchymal stromal/stem cell (MSC)-based therapies, common treatments to attenuate inflammation in IR diseases, fail to exhibit satisfying effects on cell death in renal IR. In this study, we prepared MSC-derived exosome mimetics (EMs) carrying the mammalian target of the rapamycin (mTOR) agonist to protect kidneys in proinflammatory environments under IR conditions. The thioketal-modified EMs carried the mTOR agonist and bioactive molecules in MSCs and responsively released them in kidney IR areas. MSC-derived EMs and mTOR agonists protected kidneys synergistically from IR through alleviating inflammation, apoptosis, and ferroptosis. The current study indicates that MSC-TK-MHY1485 EMs (MTM-EM) are promising therapeutic biomaterials for renal IR injury.

The novel potential therapeutic target PSMP/MSMP promotes acute kidney injury via CCR2

Acute kidney injury (AKI) is a major worldwide health concern that currently lacks effective medical treatments. PSMP is a damage-induced chemotactic cytokine that acts as a ligand of CCR2 and has an unknown role in AKI. We have observed a significant increase in PSMP levels in the renal tissue, urine, and plasma of patients with AKI. PSMP deficiency improved kidney function and decreased tubular damage and inflammation in AKI mouse models induced by kidney ischemia-reperfusion injury, glycerol, and cisplatin. Single-cell RNA sequencing analysis revealed that Ly6Chi or F4/80lo infiltrated macrophages (IMs) were a major group of proinflammatory macrophages with strong CCR2 expression in AKI. We observed that PSMP deficiency decreased CCR2+Ly6Chi or F4/80lo IMs and inhibited M1 polarization in the AKI mouse model. Moreover, overexpressed human PSMP in the mouse kidney could reverse the attenuation of kidney injury in a CCR2-dependent manner, and this effect could be achieved without CCL2 involvement. Extracellular PSMP played a crucial role, and treatment with a PSMP-neutralizing antibody significantly reduced kidney injury invivo. Therefore, PSMP might be a therapeutic target for AKI, and its antibody is a promising therapeutic drug for the treatment of AKI.

#1945 Comparative analysis of kidney transplantation modeled using precision-cut kidney slices and kidney transplantation in pigs

Abstract Background and Aims Kidney transplants are at risk for so far unavoidable ischemia-reperfusion injury. Several experimental kidney transplantation models are available to study this injury, but all have their own limitations. Here, we describe precision-cut kidney slices (PCKS) as a novel model of kidney ischemia-reperfusion injury in comparison with pig and human kidney transplantation. Method Following bilateral nephrectomy in pigs, we applied warm ischemia (1 h), cold ischemia (20 h) and a reperfusion period (4 h) to one whole kidney undergoing transplantation to a recipient pig and, in parallel, established PCKS undergoing ischemia and modeled reperfusion. Tissues were analyzed using standard histopathology assessment by two blinded pathologists, and bulk RNAseq with gene set enrichment analysis with comparison to human kidney biopsy gene sets obtained from Gene Expression Omnibus. Results Histopathological assessment revealed the presence of some but not all morphological features of tubular injury in PCKS as seen in pig kidney transplantation. RNAseq demonstrated that the majority of changes occurred after reperfusion only, with a partial overlap between PCKS and kidney transplantation, with some differences in transcriptional response attributable to systemic inflammatory responses and immune cell migration. Comparison of PCKS and pig kidney transplantation with RNAseq data from human kidney biopsies by gene set enrichment analysis revealed that both PCKS and pig kidney transplantation reproduced the post-reperfusion pattern of human kidney transplantation. In contrast, only post-cold ischemia PCKS and pig kidney partially resembled the gene set of human acute kidney injury. Conclusion Overall, the present study established that a PCKS protocol can model kidney transplantation and its reperfusion-related damage on a histological and a transcriptomic level. PCKS may thus expand the toolbox for developing novel therapeutic strategies against ischemia-reperfusion injury.

#2906 Kidney immune cells and endothelial cells can be modulated by low-salt and high-salt diets

Abstract Background and Aims Kidney immune cells and endothelial cells are involved in pathogenesis of kidney ischemia-reperfusion injury and potential therapeutic targets to improve kidney transplant outcomes. We hypothesized that dietary salt intake can change kidney immune cells and endothelial cells. Method C57BL/6 mice were treated with normal diet, low-salt diet, or high-salt diet. After 6 weeks of allocated diets, mice were euthanized, and their kidneys were collected. Leukocyte infiltration was assessed with CD45 immunohistochemistry. Lymphocytes were isolated from kidneys and were studied by flow cytometry. Human kidney transplant tissues obtained by a protocol biopsy at 2 weeks after kidney transplantation were stained with CD45, CD3, CD20, and CD31. Expression of each marker was quantified using an automated imaging analysis system and analyzed per donors’ pre-donation 24 h urine sodium levels. Induced pluripotent stem cell-derived endothelial cells (iPSC-ECs) from healthy individuals and end-stage kidney disease (ESKD) patients were treated with different sodium concentrations, and their proliferation was assessed. Results Kidneys from mice fed with high-salt diet had higher kidney leukocytes (CD45+) than those fed with normal diet (1.9 ± 0.3% vs 0.9 ± 0.1%, P = .043). Effector-memory CD4+ T cells (normal 44.2 ± 2.6%; low-salt 57.1 ± 3.5%, P = .020; high-salt 62.1 ± 2.5% of CD4+ T cells, P = .002) and mature B cells (70.0 ± 1.5%; 79.1 ± 1.4%, P = .001; 76.7 ± 1.6% of CD19+ cells, P = .015) increased by low-salt and high-salt diets, whereas naïve CD4+ T cells deceased (45.9 ± 2.1%; 32.7 ± 3.2%, P = .016; 27.8 ± 3.1% of CD4+ T cells, P = .001) in kidneys. Human kidney transplants from donors under low-salt diet showed lower total leukocytes (CD45+, 0.3 ± 0.1% vs 0.9 ± 0.3%, P = .019) with lower T and B cells (CD3+, 1.8 ± 0.2% vs 3.5 ± 0.4%, P<.001; CD20+, 0.8 ± 0.1% vs 2.1 ± 0.6%, P = .011) and higher capillary density (CD31+, 29.0 ± 2.2% vs 16.1 ± 1.8%, P = .009) compared to those from donors under high-salt diet. The proliferation of iPSC-ECs from healthy individuals and ESKD patients after hypoxia was reduced under higher sodium concentrations. Conclusion High-salt and low-salt diets affect kidney immune cell compositions and numbers as well as endothelial cells. Reconstitution of kidney microenvironment by modifying dietary salt intake could be a novel approach to improve kidney transplant outcomes.